Retrievable jet bit with swing jets



July 23, 1968 E. A. Mom 3,393,756

RETRIEVABLE JET BIT WITH SWING JETS Filed Nov. 16. 1966 2 Sheets-Sheet l II l. 1|; 1 1 I Il IIIIII A'IIIIIIII I 7/ @II I 'I I \I'frI III I -I f I I .2 III'* "III I IZI Y II A/ I I I II\\\\\\\\\\\\\\\\\ Pr. .l

l N VEN TOR. QA/57' ,4. Moxe/ July 23, 1968 E. A. MORI BETRIEVABLE JET BIT WITH SWING JETS 2 Sheets-Sheet 2 Filed Nov. 16, 1966 INVENTOR. ERA/57 A M09/ United States Patent 3,393,756 RETRIEVABLE JET BIT WITH SWING .IETS Ernest A. Mori, Glenshaw, Pa., assignor to Gulf Research & Development Company, Pittsburgh, Pa., a corporation of Delaware Filed Nov. 16, 1966, Ser. No. 594,900 7 Claims. (CI. 175-258) ABSTRACT F THE DISCLOSURE A drill bit for hydraulic jet drilling in which a nozzle holder is supported on a nozzle holder seat in the drill bit body to permit lifting of the nozzle holder from he seat for retrieving the nozzle holder. Nozzles are mounted pivotally in the nozzle holder whereby the application of pressure within the drill bit causes pivoting of the nozzle to a position at which a high-velocity stream discharged from the nozzle will cut a groove having a diameter larger than the drill bit body.

This invention relates to an apparatus for the hydraulic jet drilling of wells.

A recent development for drilling formations is to utilize abrasive-laden liquid as a drilling fluid and bombard the bottom of the borehole with this liquid by passing it through nozzles at extremely high velocities of at least 500 feet per second. In the operation of heretofore employed jet bits the outlet of the nozzles is maintained within a close and carefully controlled distance from the bottom of the borehole to prevent dissipation of the impact energy in the high-velocity stream of abrasive-laden liquid discharged from the nozzles and to reduce erosion of the bit by back splash of the abrasive-laden liquid against the -bottom of the bit. The drill string is rotated to rotate the bit and cause the exit points of the highvelocity streams to travel over the bottom of the borehole to cut a borehole of the desired diameter. Drilling liquid downwardly discharged from the nozzles cuts, substantially by impact, overlapping or continuous grooves. Virtually the entire removal of rock from the bottom of the hole is thereby accomplished by the initial bombardment of the streams of drilling liquid.

Other jet bits have been designed whose nozzles cut a plurality of concentric vertical grooves separated by intervening annular ridges. The proper interval of separation between the nozzle outlet and the formation is maintained by standol bars mounted on the bottom of the jet bit. The leading edge of the standoff bars mechanically break the intervening ridges.

These heretofore employed bits must be removed from the bottom of the borehole when their nozzles become damaged or worn. To accomplish removal, the entire string of drill pipe must be pulled from the hole and rerun with a new or repaired bit installed on its lower end. This bit change operation requires a great deal of time and supervision. This necessary bit change operation also func tions to seriously decrease the amount of borehole that can be drilled per day.

This invention resides in an improved hydraulic jet drilling apparatus in which the nozzles are contained within a nozzle body which may be removed from the well without pulling the drill pipe. To permit removal of the nozzle holder and maintain proper nozzle standoff during drilling operations, the nozzle holder of this invention contains a series of concentrically placed differential area swing nozzles. These swing nozzles, owing to their design, will swing outwardly with the initiation of uid through the bit, but when pressure is released will swing to a vertical position to permit withdrawal of the nozzle holder through the drill pipe which has a larger 3,393,756 Patented July 23, 1968 ICC inside diameter than the outside diameter of the nozzle holder. It is necessary for the nozzles to swing to an outward position during drilling operations to assure the proper standoff distance between the discharge end of the nozzles and the formation. The swing nozzles of this bit cut overlapping grooves whose outer diameter is the same as the diameter of the borehole. A series of inclined stationary nozzles are directed and positioned to cut and abrade the rock between the center of the borehole and the groove cut by the series of swing nozzles. Standotf bars are mounted on the nozzle holder to maintain the proper standoff distance between the formation and the outlet of the nozzles. A lishing neck is mounted on top of the nozzle holder to permit the removal of the nozzle body by the use of an overshot run on a wire line.

In the drawings:

FIGURE l is a diagrammatic view, partially in cross section, taken along section line I-I of FIGURE 2, of the drill bit of this invention located in the borehole of the well.

FIGURE 2 is a plan view of the top of the nozzle holder used in the bit of this invention.

Referring to FIGURE l, in which a bit of this invention is illustrated, the drill bit 2 has a central opening 4 extending upwardly through the lbit 2 for communicating with the opening of the drill string 6. The lower end of the opening 4 is closed by a nozzle holder 8. Short concentrically shaped standoff bars 10 are positioned around the bottom of the nozzle holder 8. These standoff bars 10 are protected from abrasion by mounting hard abrasive-resistant material 11, such as tungsten carbide, on their outer surface. The -bottom of the drill bit 2 and the nozzle holder 8 are likewise protected from abrasion.

A seating shoulder 12 is formed on the inside lower portion of the drill bit 2 to contact a nozzle holder seat 14 formed on the outer periphery of the nozzle holder 8. A sealing ring of rubber 13, or other deformable material, is placed between the seating shoulder 12 and the nozzle holder seat 14 thereby effecting a fluid seal and causing lluid to pass through the plurality of nozzles. Outwardly extending differential area swing nozzles, generally indicated by numerals 16 and 22 with nozzle inserts 18, as preferred in this invention, are installed through the nozzle holder 8. The lluid passageways of the swing nozzles 16 and 22 are positioned eceentrically through the nozzle holder 8 thereby causing the swing nozzles 16, 18 to pivot outwardly as pressure is applied to the top of the nozzle holder. As the pressure is released from the drill string 6 the discharge end of the swing nozzles 16, 18 will swing downwardly to a position which will allow recovery of the nozzle holder I8 through the drill string 6. A fishing neck 20 is mounted on the top of the nozzle holder to ybe used to remove the nozzle holder 8 from the well.

Numeral 30 represents the overlapping groove cut by the abrasive-laden fluid stream discharged from swing nozzle series 22. Swing nozzle series 16 will cut the overlapping grooves 32. The inwardly directed stationary nozzle series 28 will cut and abrade an overlapping groove, indicated by numeral 34. The center of the borehole will be removed by abrasive-laden uid discharged from nozzle series 24. Nozzle series 26 Will cut an overlapping groove 36 rand remove the rock between the grooves cut by nozzle -series 28 and 24.

The abrasive-laden drilling liquid is passed through the drill string, t-he drill bit 14 and discharged from the nozzles at a rate of at least 500 feet per second resulting in a pressure drop through the nozzles of the drill bit of the order of at least 2.000 pounds per square inch to impart the desired high velocity fto the drilling liquid discharged from the nozzles. The drill string Iand the d-rill bit are rotated during the drilling operations whereby the highvelocity streams of drilling liquid discharged from the nozzles cut a series of overlapping concentric grooves whose outer diameter is substantially the diameter of the borehole.

FIGURE 2 shows the concentric placement of the nozzle inlets and the nozzle holder 8. A series of out wardly extending differential area swing nozzles, indicated by numeral 22, are positioned to cut a groove in the formation whose outer diameter is substantially the same as the diameter of the borehole. A second series of outwardly extending differential area swing nozzles, indicated by numeral 16, are positioned to cut a groove in a formation whose outer diameter overlaps the groove cut by nozzle series 22. Other series of nozzles 24, 26, 28, with circumferentially positioned inlets, are directed and positioned to cut and abrade the rock between the center of rotation of the bit and the groove cut by the series of swing nozzles 16.

The swing nozzles are pivotally mounted through the nozzle holder 8 with their fluid passageways eccentrically positioned in nozzle supports 15. A slot 11 is formed through the nozzle holder 8 extending outwardly to the later-al surface of the nozzle holder 8 thereby permitting the swing nozzle to pivot outwardly as pressure is applied to the top of the nozzle holder 8.

As preferred in this bit, stationary downwardly and inwardly directed nozzles 24 are directed to cut and abrade the center of the borehole. Stationary downwardly and inwardly directed nozzles 28 are positioned to cut and abrade a groove whose outer diameter will overlap the inner ldiameter of the `groove cut by swing nozzles 16. Stationary downwardly and inwardly directed nozzles 26 are positioned to cut and abrade an overlapping groove and remove the rock between the grooves cut by stationary nozzles 28 and 24.

During drilling operations the pressure on top of the nozzle holder will cause the swing nozzles to swing out wardly through slots formed through the nozzle holder and thereby be in `a proper position and at a proper standolf distance to cut and abrade the outer extremes of the borehole. The proper standoff distance of the series of swing nozzles which cut the outermost groove in the borehole will be a position whose distance from the center of rotation is greater than inside radius of the bit body. As pressure is released from the drill string the discharge end of the swing nozzles will swing downwardly to a position which will permit recovery of the nozzle holder upward through the drill string.

A worn or damaged nozzle holder may be recovered at the surface by utilizing a wire line operated catch tool. An overshot, attached to a wire line, is run into the well and attached to the fishing neck mounted on top of the nozzle holder. The drill bit is then forced downwardly against the bottom of the borehole to unseat the nozzle holder from the bit body. The inside diameter of the drill pipe is larger than the inside diameter of the bit area in which the nozzle holder is seated. As the bit is bumped down the nozzle holder will be forced upward into the .portion of the bit having a larger diameter, thereby making recovery of the nozzle holder less diicult. The nozzle holder may then be pulled up the drill pipe and recovered at the surface. To insert a nozzle holder into the bit body the nozzle holder may be either run on a wire line and released or bumped down the drill string `and seated into the bit body. During insertion of the nozzle holder the swing nozzles will be resting in a substantially vertical position.

In the drilling of a well with the hydraulic jet bit of this invention, penetration is accomplished by the highvelocity streams of abrasive-laden liquid. The swing jets of this bit operate to permit the recovery of the nozzle holder through the drill pipe and allow proper nozzle standoff to be maintained during drilling operations.

Therefore I claim:

1. In apparatus for the hydraulic jet drilling of a borehole of a well by discharging high-velocity jet streams from a drill bit against the bottom of the borehole, an improved drill bit comprising a tubular drill bit body adapted to be connected to the lower end of drill pipe, an inwardly extending seating surface at the lower end of the drill bit body, a nozzle holder on the seating surface, a pivotally mounted nozzle support in the nozzle holder, a slot in the nozzle holder below the nozzle support extending outwardly to the lateral surface of the nozzle holder, and a nozzle eccentrically mounted in the nozzle support and extending downwardly through the slot whereby hydraulic pressure in the drill bit rotates the nozzle to an outer position to cut a groove having a larger diameter than the drill bit.

2. An apparatus for the hydraulic jet drilling of wells by discharging suspensions of abrasive particles in liquids from nozzles at a velocity of at least 500 feet per second against the bottom of the borehole comprising a hollow drill bit body, a nozzle holder seat formed on the inner surface of the drill bit body, `a retrievable nozzle holder seated in the nozzle holder seat, a swing nozzle pivotally mounted on the nozzle holder and extending there through to cut a groove whose outer diameter is larger than the outside diameter of the bit body on rotation of the bit, and a plurality of stationary nozzles set through the nozzle holder positioned to cut the bottom of the borehole between the center' thereof and the groove.

3. An apparatus for the hydraulic jet drilling of wells by discharging suspensions of `abrasive particles in liquids from retrievable nozzles at a high velocity against the bottom of the borehole comprising a hollow drill bit body, a nozzle holder seat formed on the inner surface of the bit body, a nozzle holder in contact with the nozzle holder seat, a first swing nozzle pivotally mounted on the nozzle holder and extending therethrough to cut a groove whose outer diameter is substantially the same as the diameter of the borehole, a second swing nozzle pivotally mounted on the nozzle Iholder and extending therethrough to cut a groove whose outer diameter overlaps the groove cut by the first swing nozzle and whose inner diameter is less radially remote than the groove cut by the first swing nozzle, and a plurality of stationary nozzles set through the nozzle holder and directed to remove the rock between the center of rotation of the borehole and the groove cut by the second swing nozzle.

4. An apparatus as set forth in claim 3 in which the nozzles have a discharge diameter of @5,4112 to 1A inch.

5. An apparatus as set forth in claim 3 in which the nozzle holder is of smaller outside diameter than the inside diameter of the drill string whereby the nozzle holder may be removed from the well without pulling the drill string.

6. An apparatus as set forth in claim 3 in which the nozzle holder has nozzle inserts installed therethrough.

7. An apparatus as set forth in claim 3 in which standoff 4bars are mounted on the bottom of said nozzle holder to maintain the proper standoff distance between the discharge end of the nozzles and the formation.

References Cited UNITED STATES PATENTS 1,852,903 4/1932 Salmon 175-422 2,685,431 8/1954 James 1'75-393 2,720,390 10/1955 Brooks 175-422 JAMES A. LEPPINK, Primary Examiner. 

